Divisi
How to grow Onion
Allium cepa · Amaryllidaceae
Photo: Kasyap · CC BY-SA 4.0
Onion is a cool-season vegetable you grow for its bulb — the swollen base of the leaves — but across sub-Saharan Africa it is most often grown as an irrigated hot dry-season crop, and it stands real heat (up to about 42 °C) as long as the water never stops. You raise it first in a small nursery bed, then move the young plants out to the field. The one thing that decides everything is daylength: an onion only starts to make a bulb once the days are long enough for its type, so near the equator, where days stay short, you must plant a short-day variety — plant the wrong type and the plant grows fine green leaves and never forms a bulb. Onion has shallow roots that dry out fast, it is a weak fighter against weeds, and its worst enemy is the tiny thrips insect. Grown well and cured properly, it stores for months and is one of the best cash crops a small farm can sell.
Acabashi · CC BY-SA 4.0 
Kambai Akau · CC BY-SA 4.0
- Days to maturity
- 90–120 days
- Row spacing
- 20 cm
- Plant spacing in the row
- 7 cm
- Sowing depth
- 1–1.5 cm
These are general figures for the crop, compiled from published agronomic references including FAO and CABI. The right choice for your field depends on your soil, rainfall and the yield you are aiming for.
Will onion actually do well on your land? Check your field against every crop in the catalogue — free, no signup. Run the free crop check →
Other names for Onion
ui · shinkurt · onion · oignon · albasa · anyezi · cebola · hanyanisi · anyanese · kitunguu · anyanse · itswele · u-anyanisi
Working in buckets, bags or paces? The farming glossary turns the measures growers actually use into kilograms and hectares — what a 20 litre bucket of each crop really weighs, and how to size a field by walking it — alongside the Shona, Swahili, Ndebele and Yoruba words used in the field. Open the glossary →
Growing onion, stage by stage
Your onion season from nursery bed to store — raise strong seedlings, match the variety to your daylength, keep the shallow roots steadily watered, beat the thrips, and cure the bulbs so they keep for months.
- Raise strong seedlings in a nursery bed
- Prepare the field while the nursery grows
- Transplant and settle the young plants in
- Build the leaves — every leaf is a bulb ring
- Swell the bulbs — the make-or-break stage
- Let the crop mature and dry down
- Lift the bulbs
- Cure and store the bulbs
19 step-by-step tasks in the app
Every task for onion — what to do, when to do it and why it matters — with the amounts worked out for your own field, reminders as each one falls due, and warnings before extreme weather.
Pests and diseases that attack onion
8 more threats tracked in the app
Divisi tells you which of these is a risk on your onion right now, when to walk the field looking for it, and what to do the moment you find it.
Frequently asked questions
How long does onion take to grow?
Onion takes about 90–120 days from sowing to maturity, though the exact length varies with variety, temperature and how the season runs.
What spacing should I use for onion?
Space onion rows about 20 cm apart, with roughly 7 cm between plants within the row.
How deep should onion be planted?
Sow onion at about 1–1.5 cm deep. Shallower risks drying out; deeper wastes seed energy before the shoot reaches light.
What pests and diseases attack onion?
The ones covered in this guide are Alternaria leaf blight, Bacterial soft rot, Botrytis neck rot. Each has its own page explaining how to identify, scout for and control it.
Grow onion with a plan, not a guess
Divisi turns this guide into a dated plan for your own field — what to do each week, reminders as tasks fall due, and warnings before extreme weather. Free for farmers, works offline.
Or check your field first